Is it normal for your glasses prescription to differ from contact lenses one?

Fiii

Hi there

As the title says really.
I had my eyes retested in Dec '08 and was told my prescription had gone up from L -1.50 and R -2.25 to L -1.75 and R -2.50. Bought myself new glasses and went on my newly improved eyesight merry way!

Popped back into my optician the other day to pick up some contact lenses. I still had some left over from my old prescription, so had been using them until now. Told them I was having no issues, just that I needed some in my new prescription.
Hadn't had a checkup in a year, so had that first and she told me that I had slight astigmatism and that I could either stick with the lenses I had been using, or I could go for more expensive ones that would make vision a bit clearer when wearing the lenses. She said the new lenses would be bigger and might take more getting used to.
I decided to stick with what I had been using, as other than the fact that the ones I had been using were the wrong prescription, I didn't have any problems with them.

It wasn't until I got home and looked at the lens prescription and the glasses prescription that I realised they were different.
My lenses are now L -2.00 and R -2.75.

Now there is a difference in my eyesight when I wear the glasses and the lenses, as in the glasses are better than the lenses, but only mildly.
Is this just the astigmatism, or has she messed up and given me the wrong prescription?
Is it normal for the two prescriptions to be different?
Seeing as the first jump in Dec '08 was the only jump in 4 years, I can't imagine that my eyes have gotten worse in just 9 months (even if it is just .25), but I could be wrong!

Thanks,
Fiona

Tallon

Yep, they're different because glasses are further from your eyes than contacts
Totally normal

Fiii

Good stuff.
Thanks Tallon

littlebug

is the contact lens prescription not usually lower than the glasses one